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

Toward better understanding and management of chemobrain: the potential utilities of the MemTrax memory test

OBJECTIVE

To study the effects of chemotherapy on cognitive function in breast cancer patients, and to investigate the relationship of MemTrax test of memory and related functions to the FACT-Cog functional self-assessment for the evaluation and management of chemobrain.

METHODS

In this prospective cohort study, clinical information of pathologically confirmed female breast cancer patients who decided to receive chemotherapy were collected in a questionnaire which was developed for this study and provided as a supplementary file. The FACT-Cog self-assessment and MemTrax test were administered before and after the chemotherapy treatments. Patients with chemobrain were identified using published criteria based on FACT-Cog scores, and MemTrax scores from chemobrain patients were analyzed.

RESULTS

Fifty-six patients participated in this study, of which 41 participants completed 4 or more cycles of chemotherapy and were included in the final analyses here. Using the reported high end of minimal clinical differences (10.6 points) of FACT-Cog before and after chemotherapy, 18 patients suffered from chemobrain in this study. In these 18 chemobrain patients, no cognitive impairments were detected by MemTrax, which paradoxically demonstrated an improvement in the normal cognitive range.

CONCLUSION

The cognitive impairment induced by chemotherapy in breast cancer patients is detectable by the FACT-Cog in a Chinese cohort but is not detected by the MemTrax memory test. The fact that the more objective MemTrax could not detect the impairment could alleviate patients' concerns which in turn would be beneficial for patients' mental health.

Potential of Natural Phenolic Compounds against Doxorubicin-Induced Chemobrain: Biological and Molecular Mechanisms Involved

Chemotherapy-induced cognitive impairment or "chemobrain" is a prevalent long-term complication of chemotherapy and one of the more devastating. Most of the studies performed so far to identify the cognitive dysfunctions induced by antineoplastic chemotherapies have been focused on treatment with anthracyclines, frequently administered to breast cancer patients, a population that, after treatment, shows a high possibility of long survival and, consequently, of chemobrain development. In the last few years, different possible strategies have been explored to prevent or reduce chemobrain induced by the anthracycline doxorubicin (DOX), known to promote oxidative stress and inflammation, which have been strongly implicated in the development of this brain dysfunction. Here, we have critically analyzed the results of the preclinical studies from the last few years that have evaluated the potential of phenolic compounds (PheCs), a large class of natural products able to exert powerful antioxidant and anti-inflammatory activities, in inhibiting DOX-induced chemobrain. Several PheCs belonging to different classes have been shown to be able to revert DOX-induced brain morphological damages and deficits associated with learning, memory, and exploratory behavior. We have analyzed the biological and molecular mechanisms implicated and suggested possible future perspectives in this research area.

Effect of vitamin E on doxorubicin and paclitaxel-induced memory impairments in male rats

PURPOSE

In addition to peripheral neuronal dysfunction, conventional chemotherapy can be associated with other neurological treatment-limiting adverse effects, including cognitive dysfunction, memory impairment, and anxiety, which are referred to as "chemobrain". This study aimed to investigate the effects of doxorubicin (DOX) and paclitaxel (PAC) on learning and memory in rats using radial arm water maze (RAWM) and investigated a potential beneficial effect of vitamin E (Vit. E).

METHODS

Adult male rats were injected with four doses of 2 mg/kg/week DOX, or 2 mg/kg PAC every other day intraperitoneally. Vit. E was co-administered with these drugs in other groups to study its antioxidative effects. Using the RAWM, each rat was assessed for learning and memory performance through two sets of six trials separated by a 5-min rest period evaluating both short- and long-term effects on memory.

RESULTS

There was no deficit in learning or long-term memory in both drug groups compared to control. However, rats in both drug groups made significantly more errors in all short-term memory trials. This effect was mitigated when Vit. E was co-administered with either drug. Moreover, PAC (but not DOX) induced hippocampal lipid peroxidation by increasing the levels of standard biomarker thiobarbituric acid reactive substances (TBARS). Interestingly, Vit. E prevented PAC-induced hippocampal oxidative stress. Furthermore, both DOX and PAC were correlated with reduction in Brain-Derived Neurotrophic Factor (BDNF) expression levels in the hippocampus, which was overcome by the co-administration of Vit. E.

CONCLUSION

There is a potential role of Vit. E in alleviating short-term memory impairment in rats exposed to chemotherapy, possibly by reducing hippocampal oxidative stress and neurodegeneration.

E-Stilbenes: General Chemical and Biological Aspects, Potential Pharmacological Activity Based on the Nrf2 Pathway

Stilbenes are phytoalexins, and their biosynthesis can occur through a natural route (shikimate precursor) or an alternative route (in microorganism cultures). The latter is a metabolic engineering strategy to enhance production due to stilbenes recognized pharmacological and medicinal potential. It is believed that in the human body, these potential activities can be modulated by the regulation of the nuclear factor erythroid derived 2 (Nrf2), which increases the expression of antioxidant enzymes. Given this, our review aims to critically analyze evidence regarding E-stilbenes in human metabolism and the Nrf2 activation pathway, with an emphasis on inflammatory and oxidative stress aspects related to the pathophysiology of chronic and metabolic diseases. In this comprehensive literature review, it can be observed that despite the broad number of stilbenes, those most frequently explored in clinical trials and preclinical studies (in vitro and in vivo) were resveratrol, piceatannol, pterostilbene, polydatin, stilbestrol, and pinosylvin. In some cases, depending on the dose/concentration and chemical nature of the stilbene, it was possible to identify activation of the Nrf2 pathway. Furthermore, the use of some experimental models presented a challenge in comparing results. In view of the above, it can be suggested that E-stilbenes have a relationship with the Nrf2 pathway, whether directly or indirectly, through different biological pathways, and in different diseases or conditions that are mainly related to inflammation and oxidative stress.

Nrf2 Signaling Pathway: a Potential Therapeutic Target in Combating Oxidative Stress and Neurotoxicity in Chemotherapy-Induced Cognitive Impairment

Chemotherapy-induced cognitive impairment (CICI) is one of the major adverse effects of antineoplastic drugs, which decrease the quality of life in cancer survivors. Extensive experimental and clinical research suggests that chemotherapeutic drugs generate an enormous amount of reactive oxygen species (ROS), contributing to oxidative stress, neuroinflammation, blood-brain barrier (BBB) disruption, and neuronal death, eventually leading to CICI. Despite the progress in exploring different pathological mechanisms of CICI, effective treatment to prevent CICI progression has not been developed yet. Nrf2 is the principal transcription factor that regulates cellular redox balance and inflammation-related gene expression. Emerging evidence suggests that upregulation of Nrf2 and its target genes could suppress oxidative stress, and neuroinflammation, restore BBB integrity, and increase neurogenesis. This review discusses the role of Nrf2 in CICI, how it responds to oxidative stress, inflammation, neurotoxicity, and potential Nrf2 activators that could be used to enhance Nrf2 activation in CICI.

Natural products for the treatment of chemotherapy-related cognitive impairment and prospects of nose-to-brain drug delivery

Chemotherapy-related cognitive deficits (CRCI) as one of the common adverse drug reactions during chemotherapy that manifest as memory, attention, and executive function impairments. However, there are still no effective pharmacological therapies for the treatment of CRCI. Natural compounds have always inspired drug development and numerous natural products have shown potential therapeutic effects on CRCI. Nevertheless, improving the brain targeting of natural compounds in the treatment of CRCI is still a problem to be overcome at present and in the future. Accumulated evidence shows that nose-to-brain drug delivery may be an excellent carrier for natural compounds. Therefore, we reviewed natural products with potential anti-CRCI, focusing on the signaling pathway of these drugs' anti-CRCI effects, as well as the possibility and prospect of treating CRCI with natural compounds based on nose-to-brain drug delivery in the future. In conclusion, this review provides new insights to further explore natural products in the treatment of CRCI.

Polydatin inhibits mitochondrial damage and mitochondrial ROS by promoting PINK1-Parkin-mediated mitophagy in allergic rhinitis

Polydatin (PD), a natural product derived from Polygonum cuspidatum, has anti-inflammatory and antioxidant effects and has significant benefits in treating allergic diseases. However, its role and mechanism in allergic rhinitis (AR) have not been fully elucidated. Herein, we investigated the effect and mechanism of PD in AR. AR model was established in mice with OVA. Human nasal epithelial cells (HNEpCs) were stimulated with IL-13. HNEpCs were also treated with an inhibitor of mitochondrial division or transfected with siRNA. The levels of IgE and cellular inflammatory factors were examined by enzyme linked immunosorbent assay and flow cytometry. The expressions of PINK1, Parkin, P62, LC3B, NLRP3 inflammasome proteins, and apoptosis proteins in nasal tissues and HNEpCs were measured by Western blot. We found that PD suppressed OVA-induced epithelial thickening and eosinophil accumulation in the nasal mucosa, reduced IL-4 production in NALF, and regulated Th1/Th2 balance. In addition, mitophagy was induced in AR mice after OVA challenge and in HNEpCs after IL-13 stimulation. Meanwhile, PD enhanced PINK1-Parkin-mediated mitophagy but decreased mitochondrial reactive oxygen species (mtROS) production, NLRP3 inflammasome activation, and apoptosis. However, PD-induced mitophagy was abrogated after PINK1 knockdown or Mdivi-1 treatment, indicating a key role of the PINK1-Parkin in PD-induced mitophagy. Moreover, mitochondrial damage, mtROS production, NLRP3 inflammasome activation, and HNEpCs apoptosis under IL-13 exposure were more severe after PINK1 knockdown or Mdivi-1 treatment. Conclusively, PD may exert protective effects on AR by promoting PINK1-Parkin-mediated mitophagy, which further suppresses apoptosis and tissue damage in AR through decreasing mtROS production and NLRP3 inflammasome activation.

The effectiveness of anti-inflammatory agents in reducing chemotherapy-induced cognitive impairment in preclinical models - A systematic review

Chemotherapy-induced cognitive impairment (CICI) is a debilitating condition resulting from chemotherapy administration for cancer treatment. CICI is characterised by various cognitive impairments, including issues with learning, memory, and concentration, impacting quality of life. Several neural mechanisms are proposed to drive CICI, including inflammation, therefore, anti-inflammatory agents could ameliorate such impairments. Research is still in the preclinical stage; however, the efficacy of anti-inflammatories to reduce CICI in animal models is unknown. Therefore, a systematic review was conducted, with searches performed in PubMed, Scopus, Embase, PsycInfo and Cochrane Library. A total of 64 studies were included, and of the 50 agents identified, 41 (82%) reduced CICI. Interestingly, while non-traditional anti-inflammatory agents and natural compounds reduced impairment, the traditional agents were unsuccessful. Such results must be taken with caution due to the heterogeneity observed in terms of methods employed. Nevertheless, preliminary evidence suggests anti-inflammatory agents could be beneficial for treating CICI, although it may be critical to think beyond the use of traditional anti-inflammatories when considering which specific compounds to prioritise in development.

Vildagliptin restores cognitive function and mitigates hippocampal neuronal apoptosis in cisplatin-induced chemo-brain: Imperative roles of AMPK/Akt/CREB/ BDNF signaling cascades

Cisplatin (CP) is a broad-spectrum antineoplastic agent used to treat many human cancers. Nonetheless, most patients receiving CP suffer from cognitive deficits, a phenomenon termed "chemo-brain". Recently, vildagliptin (Vilda), a DPP-4 inhibitor, has demonstrated promising neuroprotective properties against various neurological diseases. Therefore, the present study aims to investigate the potential neuroprotective properties of Vilda against CP-induced neurotoxicity and elucidate the underlying molecular mechanisms. Chemo-brain was induced in Sprague-Dawley rats by i.p injection of CP at a dose of 5 mg/kg once weekly for four weeks. Vilda was administered daily at a dose (10 mg/kg; P.O) for four weeks. The results revealed that Vilda restored the cognitive function impaired by CP, as assessed by the Morris water maze, Y-maze, and passive avoidance tests. Moreover, Vilda alleviated the CP-induced neurodegeneration, as shown by toluidine blue staining, besides markedly reduced amyloid plaque deposition, as evidenced by Congo red staining. Notably, Vilda boosted cholinergic neurotransmission through the downregulation of the acetylcholinesterase enzyme. In addition, the neuroprotective mechanisms of Vilda include diminishing oxidative stress by reducing MDA levels while raising GSH levels and SOD activity, repressing neuronal apoptosis as shown by elevated Bcl-2 levels together with diminished Bax and caspase-3 expressions, inhibiting neuroinflammation as shown by decreased GFAP expression, and finally boosting hippocampal neurogenesis and survival by upregulating expressions of BDNF and PCNA. These effects were mainly mediated by activating AMPK/Akt/CREB signaling cascades. In summary, Vilda can be considered a promising candidate for guarding against CP-induced chemo-brain and neurodegeneration, thus improving the quality of life of cancer patients.

Resveratrol Improves Paclitaxel-Induced Cognitive Impairment in Mice by Activating SIRT1/PGC-1α Pathway to Regulate Neuronal State and Microglia Cell Polarization

Objective

This study aimed to investigate the effect of resveratrol (Res) on paclitaxel (PTX)-induced cognitive impairment and elucidate the underlying molecular mechanisms.

Methods

Morris Water Maze (MWM) test was used to evaluate the mice's spatial learning and memory abilities. Western blotting was applied to detect protein expression of receptor-interacting protein (RIP3), mixed lineage kinase domain-like protein (MLKL), silencing information regulator 2 related enzyme 1 (SIRT1), peroxisome proliferator activated receptor coactivator-1 (PGC-1α), NADPH oxidase 2 (NOX2), NOX4, postsynaptic density zone 95 (PSD95), arginase-1 (Arg-1) and inducible nitric oxide synthase (iNOS). Immunofluorescence of RIP3, MLKL, Arg-1, Iba-1 and iNOS was conducted to observe the apoptosis of hippocampal cells and the polarization of microglia. qRT-PCR was performed to detect BDNF mRNA expressions. DHE staining was used to assess the level of oxidative stress response. Golgi-Cox staining and dendritic spine counting were applied to visualize synaptic structural plasticity. Postsynaptic density was performed by transmission electron microscope. ELISA was used to detect the contents of tumour necrosis factor alpha (TNF-α), IL-1β, IL-4, and IL-10.

Results

PTX-induced cognitive impairment model was constructed after the application of PTX, represented as longer latency to platform and less platform crossing times over the whole period in PTX group. After Res treatment, the above indicators were reversed, indicating that cognitive function was improved. Moreover, Res reduced neuronal apoptosis and oxidative stress through SIRT1/PGC-1α pathway in mice, manifesting as down-regulated expression of RIP3, MLKL, NOX2 and NOX4. Meanwhile, Res increased the density of dendritic spines and the expression of PSD95 and BDNF, thereby ameliorating the PTX induced synaptic damage. Besides, M2 microglia was in the majority, eliciting the expression of anti-inflammatory cytokines IL-4 and IL-10 after Res treatment in PTX+Res group, while immunofluorescence images results demonstrated an decrease in the proportion of M2 microglia a following SIRT1 inhibitor EX-527.

Conclusion

Res improves PTX-induced cognitive impairment in mice by activating SIRT1/PGC-1α pathways to regulate neuronal state and microglia cell polarization.

Why Is Longevity Still a Scientific Mystery? Sirtuins-Past, Present and Future

The sirtuin system consists of seven highly conserved regulatory enzymes responsible for metabolism, antioxidant protection, and cell cycle regulation. The great interest in sirtuins is associated with the potential impact on life extension. This article summarizes the latest research on the activity of sirtuins and their role in the aging process. The effects of compounds that modulate the activity of sirtuins were discussed, and in numerous studies, their effectiveness was demonstrated. Attention was paid to the role of a caloric restriction and the risks associated with the influence of careless sirtuin modulation on the organism. It has been shown that low modulators' bioavailability/retention time is a crucial problem for optimal regulation of the studied pathways. Therefore, a detailed understanding of the modulator structure and potential reactivity with sirtuins in silico studies should precede in vitro and in vivo experiments. The latest achievements in nanobiotechnology make it possible to create promising molecules, but many of them remain in the sphere of plans and concepts. It seems that solving the mystery of longevity will have to wait for new scientific discoveries.

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.

Polydatin: Pharmacological Mechanisms, Therapeutic Targets, Biological Activities, and Health Benefits

Polydatin is a natural potent stilbenoid polyphenol and a resveratrol derivative with improved bioavailability. Polydatin possesses potential biological activities predominantly through the modulation of pivotal signaling pathways involved in inflammation, oxidative stress, and apoptosis. Various imperative biological activities have been suggested for polydatin towards promising therapeutic effects, including anticancer, cardioprotective, anti-diabetic, gastroprotective, hepatoprotective, neuroprotective, anti-microbial, as well as health-promoting roles on the renal system, the respiratory system, rheumatoid diseases, the skeletal system, and women's health. In the present study, the therapeutic targets, biological activities, pharmacological mechanisms, and health benefits of polydatin are reviewed to provide new insights to researchers. The need to develop further clinical trials and novel delivery systems of polydatin is also considered to reveal new insights to researchers.

[Effect of polydatin on the proliferation and apoptosis of THP-1 cells and the mechanism]

OBJECTIVES

To explore the effect of polydatin on the proliferation and apoptosis of acute monocytic leukemia cell line THP-1 and the possible mechanism.

METHODS

After THP-1 cells were treated with polydatin at gradient concentrations for 24 hours and 48 hours, their proliferation was determined by CCK-8 assay, and half maximal inhibitory concentration (IC50) was calculated. Logarithmically growing THP-1 cells were divided into two groups, a polydatin treatment group (treated with IC50 of polydatin) and a blank control group (treated without polydatin solution), and incubated for 48 hours. Cell apoptosis and cell cycle were measured by flow cytometry. The expression levels of PI3K, AKT, p-AKT, mTOR, p-mTOR, p70 S6K, and p-p70 S6K proteins were measured by Western blotting.

RESULTS

After treatment with polydatin, the proliferation of THP-1 cells was strongly inhibited, and the IC50 at 48 hours was 1 800 μmol/L. After treatment with 1 800 μmol/L polydatin solution for 48 hours, the apoptosis rate of THP-1 cells increased significantly compared with the blank control group (P<0.05). The cell cycle was arrested in the G0/G1 and S phases, with a significantly increased proportion of cells in the G0/G1 phase and a significantly decreased proportion of cells in the S phase, as compared with the blank control group (P<0.05). The expression levels of PI3K, AKT, p-AKT, mTOR, p-mTOR, p70 S6K, and p-p70 S6K proteins decreased significantly compared with the blank control group (P<0.05).

CONCLUSIONS

Polydatin can effectively inhibit the proliferation, block the cell cycle, and induce the apoptosis of THP-1 cells, which may be related to inhibition of the PI3K/AKT/mTOR signaling pathway.

Polydatin as a therapeutic alternative for central nervous system disorders: A systematic review of animal studies

Polydatin, or piceid, is a natural stilbene found in grapes, peanuts, and wines. Polydatin presents pharmacological activities, including neuroprotective properties, exerting preventive and/or therapeutic effects in central nervous system (CNS) disorders. In the present study, we summarize and discuss the neuroprotective effects of polydatin in CNS disorders and related pathological conditions in preclinical animal studies. A systematic review was performed by searching online databases, returning a total of 110 records, where 27 articles were selected and discussed here. The included studies showed neuroprotective effects of polydatin in experimental models of neurological disorders, including cerebrovascular disorders, Parkinson's disease, traumatic brain injuries, diabetic neuropathy, glioblastoma, and neurotoxicity induced by chemical agents. Most studies were focused on stroke (22.2%) and conducted in male rodents. The intervention protocol with polydatin was mainly acute (66.7%), with postdamage induction treatment being the most commonly used regimen (55.2%). Overall, polydatin ameliorated behavioral dysfunctions and/or promoted neurological function by virtue of its antioxidant and antiinflammatory properties. In summary, this review offers important scientific evidence for the neuroprotective effects and distinct pharmacological mechanisms of polydatin that not only enhances the present understanding but is also useful for the development of future preclinical and clinical investigations.

Chemobrain in Breast Cancer: Mechanisms, Clinical Manifestations, and Potential Interventions

Among the potential adverse effects of breast cancer treatment, chemotherapy-related cognitive impairment (CRCI) has gained increased attention in the past years. In this review, we provide an overview of the literature regarding CRCI in breast cancer, focusing on three main aspects. The first aspect relates to the molecular mechanisms linking individual drugs commonly used to treat breast cancer and CRCI, which include oxidative stress and inflammation, reduced neurogenesis, reduced levels of specific neurotransmitters, alterations in neuronal dendrites and spines, and impairment in myelin production. The second aspect is related to the clinical characteristics of CRCI in patients with breast cancer treated with different drug combinations. Data suggest the incidence rates of CRCI in breast cancer vary considerably, and may affect more than 50% of treated patients. Both chemotherapy regimens with or without anthracyclines have been associated with CRCI manifestations. While cross-sectional studies suggest the presence of symptoms up to 20 years after treatment, longitudinal studies confirm cognitive impairments lasting for at most 4 years after the end of chemotherapy. The third and final aspect is related to possible therapeutic interventions. Although there is still no standard of care to treat CRCI, several pharmacological and non-pharmacological approaches have shown interesting results. In summary, even if cognitive impairments derived from chemotherapy resolve with time, awareness of CRCI is crucial to provide patients with a better understanding of the syndrome and to offer them the best care directed at improving quality of life.

Old dog, new tricks: Polydatin as a multitarget agent for current diseases

Polydatin (PD) is a natural single-crystal product that is primarily extracted from the traditional plant Polygonum cuspidatum Sieb. et Zucc. Early research showed that PD exhibited a variety of biological activities. PD has attracted increasing research interest since 2014, but no review comprehensively summarized the new findings. A great gap between its biological activities and drug development remains. It is necessary to summarize new findings on the pharmacological effects of PD on current diseases. We propose that PD will most likely be used in cardiac and cerebral ischaemia/reperfusion-related diseases and atherosclerosis in the future. The present work classified these new findings according to diseases and summarized the main effects of PD via specific mechanisms of action. In summary, we found that PD played a therapeutic role in a variety of diseases, primarily via five mechanisms: antioxidative effects, antiinflammatory effects, regulation of autophagy and apoptosis, maintenance of mitochondrial function, and lipid regulation.

Dietary agents in mitigating chemotherapy-related cognitive impairment (chemobrain or chemofog): first review addressing the benefits, gaps, challenges and ways forward

Chemobrain or chemofog is one of the important but less investigated side effects, where the cancer survivors treated with chemotherapy develop long-term cognitive impairments, affecting their quality of life. The biological mechanisms triggering the development of chemobrain are largely unknown. However, a literature study suggests the generation of free radicals, oxidative stress, inflammatory cytokines, epigenetic chromatin remodeling, decreased neurogenesis, secretion of brain-derived neurotropic factor (BDNF), dendritic branching, and neurotransmitter release to be the cumulative contributions to the ailment. Unfortunately, there is no means to prevent/mitigate the development and intensity of chemobrain. Given the lack of effective prevention strategies or treatments, preclinical studies have been underway to ascertain the usefulness of natural products in mitigating chemobrain in the recent past. Natural products used in diets have been shown to provide beneficial effects by inhibition of free radicals, oxidative stress, inflammatory processes, and/or concomitant upregulation of various cell survival proteins. For the first time, this review focuses on the published effects of astaxanthin, omega-3 fatty acids, ginsenoside, cotinine, resveratrol, polydatin, catechin, rutin, naringin, curcumin, dehydrozingerone, berberine, C-phycocyanin, the higher fungi Cordyceps militaris, thyme (Thymus vulgaris) and polyherbal formulation Mulmina™ in mitigating cognitive impairments in preclinical models of study, and also addresses their potential neuro-therapeutic mechanisms and applications in preventing/ameliorating chemobrain.

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

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

The Neuroprotective Role of Polydatin: Neuropharmacological Mechanisms, Molecular Targets, Therapeutic Potentials, and Clinical Perspective

Neurodegenerative diseases (NDDs) are one of the leading causes of death and disability in humans. From a mechanistic perspective, the complexity of pathophysiological mechanisms contributes to NDDs. Therefore, there is an urgency to provide novel multi-target agents towards the simultaneous modulation of dysregulated pathways against NDDs. Besides, their lack of effectiveness and associated side effects have contributed to the lack of conventional therapies as suitable therapeutic agents. Prevailing reports have introduced plant secondary metabolites as promising multi-target agents in combating NDDs. Polydatin is a natural phenolic compound, employing potential mechanisms in fighting NDDs. It is considered an auspicious phytochemical in modulating neuroinflammatory/apoptotic/autophagy/oxidative stress signaling mediators such as nuclear factor-κB (NF-κB), NF-E2–related factor 2 (Nrf2)/antioxidant response elements (ARE), matrix metalloproteinase (MMPs), interleukins (ILs), phosphoinositide 3-kinases (PI3K)/protein kinase B (Akt), and the extracellular regulated kinase (ERK)/mitogen-activated protein kinase (MAPK). Accordingly, polydatin potentially counteracts Alzheimer’s disease, cognition/memory dysfunction, Parkinson’s disease, brain/spinal cord injuries, ischemic stroke, and miscellaneous neuronal dysfunctionalities. The present study provides all of the neuroprotective mechanisms of polydatin in various NDDs. Additionally, the novel delivery systems of polydatin are provided regarding increasing its safety, solubility, bioavailability, and efficacy, as well as developing a long-lasting therapeutic concentration of polydatin in the central nervous system, possessing fewer side effects.

Nose-to-brain delivery of chrysin transfersomal and composite vesicles in doxorubicin-induced cognitive impairment in rats: Insights on formulation, oxidative stress and TLR4/NF-kB/NLRP3 pathways

Many cancer survivors suffer from chemotherapy-induced cognitive impairment known as 'Chemobrain'. Doxorubicin -topoisomerase II inhibitor- is widely used in breast cancer, hematological cancers and other neoplasms. However, it is reported to precipitate cognitive impairment in cancer patients via inducing oxidative stress and inflammatory response. Chrysin -5,7 dihydroxyflavone- has promising antioxidant, anti-inflammatory and anticancer properties, but suffers low bioavailability owing to its poor solubility and extensive metabolism. In the present study, chrysin was successfully formulated as transfersomal lipid vesicles and chitosan composite vesicles (CCV) exhibiting a nanometric size range, high drug entrapment efficiency, and controlled release over a 72h period. Intranasal administration of optimized chrysin formulations at a reduced dose of 0.5 mg/kg improved doxorubicin-induced memory impairment in rats evidenced by behavioral testing, inhibition of acetylcholinesterase activity and oxidative stress markers; catalase, reduced glutathione, lipid peroxidation and hydrogen peroxide. This could reduce caspase-3 expression inhibiting apoptosis. Moreover, chrysin formulations were able to inhibit doxorubicin-induced Tol-like receptor 4 (TLR4) and p65 subunit of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) protein expression which in turn, reduced procaspase-1, Cysteinyl Aspartate Protease-1 (caspase-1) and Interleukin-1β (IL-1β) protein expression via inhibiting Nod-like receptor pyrin containing 3 (NLRP3) inflammasome. Collectively, our findings suggest the enhanced therapeutic potential of chrysin when formulated as transfersomes and CCV against chemotherapy-induced chemobrain via hindering acetylcholinesterase, oxidative stress and TLR4-NF-kB(p65)-NLRP3 pathways.

Micronutrient Food Supplements in Patients with Gastro-Intestinal and Hepatic Cancers

Colorectal carcinogenesis is the second most common cause of mortality across all types of malignancies, followed by hepatic and stomach cancers. Chemotherapy and radiotherapy are key approaches to treating cancer patients, but these carry major concerns, such as a high risk of side effects, poor accessibility, and the non-selective nature of chemotherapeutics. A number of natural products have been identified as countering various forms of cancer with fewer side effects. The potential impact of vitamins and minerals on long-term health, cognition, healthy development, bone formation, and aging has been supported by experimental and epidemiological studies. Successful treatment may thus be highly influenced by the nutritional status of patients. An insufficient diet could lead to detrimental effects on immune status and tolerance to treatment, affecting the ability of chemotherapy to destroy cancerous cells. In recent decades, most cancer patients have been taking vitamins and minerals to improve standard therapy and/or to decrease the undesirable side effects of the treatment together with the underlying disease. On the other hand, taking dietary supplements during cancer therapy may affect the effectiveness of chemotherapy. Thus, micronutrients in complementary oncology must be selected appropriately and should be taken at the right time. Here, the potential impact of micronutrients on gastro-intestinal and hepatic cancers is explored and their molecular targets are laid down.

Oxidative Stress and Cognitive Alterations Induced by Cancer Chemotherapy Drugs: A Scoping Review

Cognitive impairment is one of the most deleterious effects of chemotherapy treatment in cancer patients, and this problem sometimes remains even after chemotherapy ends. Common classes of chemotherapy-based regimens such as anthracyclines, taxanes, and platinum derivatives can induce both oxidative stress in the blood and in the brain, and these effects can be reproduced in neuronal and glia cell cultures. In rodent models, both the acute and repeated administration of doxorubicin or adriamycin (anthracyclines) or cisplatin impairs cognitive functions, as shown by their diminished performance in different learning and memory behavioural tasks. Administration of compounds with strong antioxidant effects such as N-acetylcysteine, gamma-glutamyl cysteine ethyl ester, polydatin, caffeic acid phenethyl ester, and 2-mercaptoethane sulfonate sodium (MESNA) counteract both oxidative stress and cognitive alterations induced by chemotherapeutic drugs. These antioxidant molecules provide the scientific basis to design clinical trials in patients with the aim of reducing the oxidative stress and cognitive alterations, among other probable central nervous system changes, elicited by chemotherapy in cancer patients. In particular, N-acetylcysteine and MESNA are currently used in clinical settings and are therefore attracting scientific attention.

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.

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

RATIONALE

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

OBJECTIVES

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

RESULTS

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

CONCLUSION

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

Protective Effects of Polydatin Against Dementia-Related Disorders

Dementia is a collection of symptoms affecting a person's cognition. Dementia is debilitating, and therefore, finding an effective treatment is of utmost importance. Resveratrol, which exhibits neuroprotective effects, has low bioavailability. However, its glucoside polydatin is more bioavailable. Here, the evidence that supports the protective role of polydatin against dementia- related diseases such as Alzheimer's disease, vascular dementia, alcohol-related dementia, and Lewy body dementias is presented. The beneficial effects of polydatin from a mechanistic perspective are specifically emphasized in this review. Future directions in this area of research are also discussed.

Cancer Chemotherapy Related Cognitive Impairment and the Impact of the Alzheimer's Disease Risk Factor APOE

Cancer related cognitive impairment (CRCI) is a serious impairment to maintaining quality of life in cancer survivors. Cancer chemotherapy contributes to this condition through several potential mechanisms, including damage to the blood brain barrier, increases in oxidative stress and inflammation in the brain, and impaired neurogenesis, each of which lead to neuronal dysfunction. A genetic predisposition to CRCI is the E4 allele of the Apolipoprotein E gene (APOE), which is also the strongest genetic risk factor for Alzheimer's disease. In normal brains, APOE performs essential lipid transport functions. The APOE4 isoform has been linked to altered lipid binding, increased oxidative stress and inflammation, reduced turnover of neural progenitor cells, and impairment of the blood brain barrier. As chemotherapy also affects these processes, the influence of APOE4 on CRCI takes on great significance. This review outlines the main areas where APOE genotype could play a role in CRCI. Potential therapeutics based on APOE biology could mitigate these detrimental cognitive effects for those receiving chemotherapy, emphasizing that the APOE genotype could help in developing personalized cancer treatment regimens.

Ethanol Extract of Chinese Hawthorn (Crataegus pinnatifida) Fruit Reduces Inflammation and Oxidative Stress in Rats with Doxorubicin-Induced Chronic Heart Failure

Background

Chinese hawthorn (Crataegus pinnatifida) fruit is a traditional Chinese medicine for treatment of digestive system and cardiovascular diseases. The fruit contains polyphenol compounds, such as epicatechin, that have anti-inflammatory activity. This study aimed to investigate the effects of an alcohol extract of hawthorn fruit (HAE) on inflammation and oxidative stress in rats with doxorubicin-induced chronic heart failure (CHF).

Material/Methods

Rats were intraperitoneally injected with doxorubicin to induce CHF and subsequently treated with HAE intragastrically once daily for 6 weeks. At the end of the experiment, echocardiographic and hemodynamic parameters were assessed, and enzyme-linked immunoassays were used to detect the levels of cardiac injury markers (brain natriuretic peptide, creatine kinase-MB, aspartate aminotransferase, lactate dehydrogenase, copeptin, and adrenomedullin), oxidative stress markers (glutathione peroxidase and malondialdehyde), and inflammatory cytokines (interleukin [IL]-6, IL-8, IL-1β, and tumor necrosis factor-α). The IL-1β, IL-6, glutathione peroxidase-1, and catalase mRNA levels were also measured by quantitative real-time polymerase chain reaction.

Results

Our findings indicated that HAE exerts a cardioprotective effect, as shown by improved echocardiographic and hemodynamic parameters, decreased activity of serum myocardial enzymes, reduced serum levels of CHF markers, and inhibited inflammatory response in cardiac tissue. In addition, HAE treatment downregulated the mRNA expression of IL-1β and tumor necrosis factor-α and upregulated the mRNA expression of glutathione peroxidase-1 and catalase compared with untreated doxorubicin-induced CHF rats.

Conclusions

HAE shows promise for the prevention and treatment of CHF. The cardioprotective effect of HAE appears to be related to inhibition of both the inflammatory response and oxidative stress in vivo.