Effect of Metformin on Doxorubicin-Induced Memory Dysfunction

Enhanced antichemobrain activity of amino acid assisted ferulic acid solid dispersion in adult zebrafish (Danio rerio)

Chemotherapy-induced cognitive impairment (CICI), also known as "chemobrain," is a common side effect of breast cancer therapy which causes oxidative stress and generation of reactive oxygen species (ROS). Ferulic acid (FA), a natural polyphenol, belongs to BCS class II is confirmed to have nootropic, neuroprotective and antioxidant effects. Here, we have developed FA solid dispersion (SD) in order to enhance its therapeutic potential against chemobrain. An amorphous ferulic acid loaded leucin solid dispersion (FA-Leu SD) was prepared by utilizing amino acid through spray-drying technique. The solid-state characterization was carried out via Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). Additionally, in-vitro release studies and antioxidant assay were also performed along with in-vivo locomotor, biochemical and histopathological analysis. The physical properties showed that FA-Leu SD so formed exhibited spherical, irregular surface hollow cavity of along with broad melting endotherm as observed from FE-SEM and DSC results. The XRD spectra demonstrated absence of sharp and intense peaks in FA-Leu SD which evidenced for complete encapsulation of drug into carrier. Moreover, in-vitro drug release studies over a period of 5 h in PBS (pH 7.4) displayed a significant enhanced release in the first hr (68. 49 ± 5.39%) and in-vitro DPPH assay displayed greater antioxidant potential of FA in FA-Leu SD. Furthermore, the in-vivo behavioral findings of FA-Leu SD (equivalent to 150 mg/kg of free FA) exhibited positive results accompanied by in-vivo biochemical and molecular TNF-α showed a significant difference (p < 0.001) vis-à-vis DOX treated group upon DOX + FA-Leu SD. Additionally, histopathological analysis revealed neuroprotective effects of FA-Leu SD together with declined oxidative stress due to antioxidant potential of FA which was induced by anticancer drug doxorubicin (DOX). Overall, the above findings concluded that spray-dried FA-Leu SD could be useful for the treatment of chemotherapy induced cognitive impairment.

N-acetylcysteine ameliorates chemotherapy-induced impaired anxiety and depression-like behaviors by regulating inflammation, oxidative and cholinergic status, and BDNF release

Mood disorders caused by chemotherapy have become more important as the survival of cancer patients increases, and new studies in this field will contribute to the prevention of this disorder. For this purpose, we used methotrexate, a chemotherapeutic agent frequently preferred in oncological cases. Mtx was administered as a single dose of 100 mg/kg intraperitoneally to male Wistar albino rats. Since oxidative stress plays an important role in chemotherapy-induced emotional impairment, n-acetylcysteine (NAC), a potent antioxidant, was administered at 500 mg/kg in two doses before Mtx administration. We evaluated anxiety and depression-like behaviors 24 h after Mtx administration, as well as some oxidative and inflammatory markers in blood serum and hippocampal tissue, acetylcholinesterase activity (AChE), and brain-derived neurotrophic factor (BDNF) release in hippocampal tissue. In rats, Mtx induced anxiety and depression-like behaviors as well as abnormalities in oxidative and inflammatory markers in blood serum and hippocampal tissue, increased AChE activity in hippocampal tissue, and decreased BDNF release. NAC treatment was found to ameliorate Mtx-induced anxiety and depression-like behaviors, increase antioxidant capacity, reduce oxidative stress and inflammatory response, and regulate AChE activity and BDNF release. In conclusion, the fact that NAC treatment of Mtx was effective is important for revising the treatment strategies for individuals suffering from this disorder, and this effect is thought to be related to the antioxidant and anti-inflammatory power of NAC.

Pioglitazone ameliorates DOX-induced cognitive impairment by mitigating inflammation, oxidative stress, and apoptosis of hippocampal neurons in rats

Doxorubicin (DOX) is broadly used as a medication for cancer treatment. However, DOX has been connected with chemotherapy-related complications, for instance, cognitive impairment (chemobrain). Chemobrain developed in up to 70% of cancer patients; therapeutic is unavailable. This study investigated the preventive effect of pioglitazone (PIO) on neurotoxicity caused by (DOX) in the hippocampus. Forty rats were separated into four groups; control (normal saline 10 ml/kg), DOX (5 mg/kg, intraperitoneally every 3rd day, equivalent to 20 mg/kg cumulative dose), PIO (2 mg/kg in drinking water), and DOX+PIO (DOX, 5 mg/kg, intraperitoneally every 3rd day concurrently PIO, 2 mg/kg in drinking water) and duration of drug treatment lasted for 14 days. The animals were subjected to contextual fear memory tests to characterize the cognitive impairment following DOX treatment. ELISA assessed hippocampal protein expression related to inflammation, oxidative damage, and apoptosis. DOX-treatment produced significant reduction in freezing duration in contextual fear memory tests, which was reversed by PIO co-administration. DOX increased neuroinflammation, oxidative stress, apoptosis, and mitochondrial activity by increasing NF-κB and COX-2 levels, reducing SOD levels, and increasing Bax, caspase-3, and lipid peroxidation. However, DOX did not affect GSH or catalase levels. PIO co-administration reduces NF-κB, COX-2, MDA, Bax, and caspase-3 levels and improves mitochondrial activity and SOD expression. To sum up, DOX therapy accelerates cognitive decline in rats by increasing neuroinflammation, oxidative stress, mitochondrial dysfunction, lipid peroxidation, and apoptosis. PIO is a promising treatment for DOX-induced cognitive impairment.

Artificial and natural interventions for chemotherapy- and / or radiotherapy-induced cognitive impairment: A systematic review of animal studies

BACKGROUND

Cancer survivors frequently experience cognitive impairments. This systematic review assessed animal literature to identify artificial (pharmaceutical) or natural interventions (plant/endogenously-derived) to reduce treatment-related cognitive impairments.

METHODS

PubMed, EMBASE, PsycINFO, Web of Science, and Scopus were searched and SYRCLE's tool was used for risk of bias assessment of the 134 included articles.

RESULTS

High variability was observed and risk of bias analysis showed overall poor quality of reporting. Results generally showed positive effects in the intervention group versus cancer-therapy only group (67% of 156 cognitive measures), with only 15 (7%) measures reporting cognitive impairment despite intervention. Both artificial (61%) and natural (75%) interventions prevented cognitive impairment. Artificial interventions involving GSK3B inhibitors, PLX5622, and NMDA receptor antagonists, and natural interventions utilizing melatonin, curcumin, and N-acetylcysteine, showed most consistent outcomes.

CONCLUSIONS

Both artificial and natural interventions may prevent cognitive impairment in rodents, which merit consideration in future clinical trials. Greater consistency in design is needed to enhance the generalizability across studies, including timing of cognitive tests and description of treatments and interventions.

Treadmill exercise ameliorates chemotherapy-induced memory impairment through Wnt/β-catenin signaling pathway

Doxorubicin (DOX) is a widely used chemotherapy drug for various cancers and it is known to induce cognitive impairment. The aim of this study was to investigate the effect of treadmill exercise on chemotherapy-induced memory impairment. We assessed whether DOX affects inflammation, mitochondrial Ca2+ retention capacity, and Wnt/β-catenin signaling. Male Sprague-Dawley rats were divided into control group, exercise group, DOX-injection group, and DOX-injection and exercise group. To create a DOX-induced memory impairment model, animals were injected intraperitoneally with DOX (2 mg/kg) dissolved in saline solution once a week for 4 weeks. Treadmill exercise was performed once a day, 5 days a week, for 8 consecutive weeks. Short-term memory was determined using the step-down avoidance test. Western blot was performed for the proinflammatory cytokines, Wnt/β-catenin signaling, brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB) in the hippocampus. Mitochondrial Ca2+ retention capacity in the hippocampus was also measured. DOX-injection rats showed deterioration of short-term memory along with decreased expression of BDNF and TrkB in the hippocampus. Levels of the proinflammatory cytokines, tumor necrosis factor-α and interleukin-6, were increased in the DOX-injection rats. Wnt/β-catenin signaling was activated and mitochondrial Ca2+ retention capacity was decreased in the DOX-injection rats. However, treadmill exercise alleviated short-term memory impairment, decreased proinflammatory cytokines, increased BDNF and TrkB expression, and enhanced mitochondrial Ca2+ retention capacity. Treadmill exercise restorated Wnt/β-catenin signaling pathway. This study demonstrated that treadmill exercise can be used for patients undergoing chemotherapy with DOX.

Doxorubicin impairs cognitive function by upregulating AMPAR and NMDAR subunit expression and increasing neuroinflammation, oxidative stress, and apoptosis in the brain

Introduction: The anticancer drug doxorubicin (DOX) is used for various malignancies. However, it also causes cognitive impairment in cancer survivors. In order to determine the mechanisms underlying the acute effects of DOX, we assessed the mRNA and protein expression of glutamate receptors and proteins involved in cognitive function and apoptosis. Methods: Fear-conditioning memory tests were performed in rats after a single intraperitoneal injection of DOX (25 mg/kg) to evaluate short-term memory function. Rat brain samples were collected, and GluA1 mRNA and protein expression; NR2A and NR2B mRNA expression; and COX-2, NF-kB, TNF-α, and MDA, Bax, and caspase-3 levels were assessed via reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assays. Results: We observed a decreased number of entries in Y-maze, decreased exploration time to the novel object in the novel object recognition (NOR), and decreased freezing time in the fear-conditioning memory tests in DOX-treated rats relative to those in control rats, demonstrating cognitive impairment. GluA1, NR2B, and NR2A expression and MDA, NF-κB, Bax, COX-2, TNF-α, and caspase-3 levels in the brain were significantly elevated in DOX-treated rats. Conclusion: DOX induced cognitive impairment in the rats via neuronal toxicity by upregulating AMPAR and NMDAR expression and increasing neuroinflammation, oxidative stress, and apoptosis in the brain.

A Review on the Neurotoxic Effects of Doxorubicin

Anthracyclines, a class of drugs considered as most effective anticancer drugs, used in the various regimens of cancer chemotherapy, induce long-term impairment of mitochondrial respiration, increase reactive oxygen species, and induce other mechanisms potentially leading to neurotoxicity. According to literature findings, one drug of this class - doxorubicin used to treat e.g. breast cancer, bladder cancer, lymphoma, and acute lymphocytic leukemia may induce such effects in the nervous system. Doxorubicin has poor penetration into the brain due to the lack of drug penetration through the blood-brain barrier, thus the toxicity of this agent is the result of its peripheral action. This action is manifested by cognitive impairment and anatomical changes in the brain and peripheral nervous system found in both preclinical and clinical studies in adult patients. Furthermore, more than 50% of children with cancer are treated with anthracyclines including doxorubicin, which may affect their nervous system, and lead to lifelong damage in many areas of their life. Despite ongoing research into the side effects of this drug, the mechanism of its neurotoxicity action on the central and peripheral nervous system is still not well understood. This review aims to summarize the neurotoxic effects of doxorubicin in preclinical (in vitro and in vivo) research and in clinical studies. Furthermore, it discusses the possible mechanisms of the toxic action of this agent on the nervous system.

Comparative evaluation of doxorubicin, cyclophosphamide, 5-fluorouracil, and cisplatin on cognitive dysfunction in rats: Delineating the role of inflammation of hippocampal neurons and hypothyroidism

Chemotherapeutic agents such as doxorubicin, cyclophosphamide, fluorouracil, and cisplatin are commonly used to treat a variety of cancers and often result in chemobrain, which manifests as difficulties in learning and memory processes that can persist in the years following treatment. The current study aims to evaluate the cognitive function following treatment with these agents and the underlying mechanisms using a rat model of neuroinflammation and possible implication of thyroid toxicity in chemotherapy induced cognitive dysfunction. Wistar female rats were treated with a single dose of doxorubicin (DOX, 25 mg/kg), 5-fluorouracil (5-FU, 100 mg/kg), cisplatin (8 mg/kg), and cyclophosphamide (CYP, 200 mg/kg) by intraperitoneal injection. The cognitive performance of rats was then evaluated in spatial memory tasks using the Y-maze, novel object recognition (NOR), and elevated plus maze (EPM) tests. Serum levels of thyroid hormones (T3, T4, FT3, and FT4) and thyroid stimulating hormone (TSH) were measured, followed by estimation of TNFα, IL-6, and IL-1β in the hippocampal tissue. Results revealed that all the chemotherapeutic agents produced impairment of cognitive function, and significant increase of pro-inflammatory cytokines such as TNFα, IL-6 and IL-1β in the hippocampal tissues. There was a significant reduction in thyroid hormones (T3, FT3, and T4) and an increase in thyroid stimulating hormone (TSH) in serum, which may also have contributed to the decline in cognitive function. In conclusion, DOX, 5-FU, CYP, and cisplatin produces impairment of spatial memory possibly by inflammation of hippocampal neurons and endocrine disruption (hypothyroidism) in rats.

Protective Effect of Galantamine against Doxorubicin-Induced Neurotoxicity

BACKGROUND AND AIMS

Doxorubicin (DOX) causes cognitive impairment (chemobrain) in patients with cancer. While DOX damages the cholinergic system, few studies have focused on the protective effects of cholinergic function on chemobrain. The acetylcholinesterase inhibitor galantamine (GAL) demonstrates neuroprotective properties. We investigated the mechanisms associated with DOX-induced cognitive impairments and the potential protective role of GAL in preventing chemobrain.

MAIN METHODS

Female Wistar rats were divided into control, DOX, GAL, and DOX + GAL groups. The rats in the DOX group were administered DOX (5 mg/kg intraperitoneally twice weekly for two weeks), while those in the GAL group were orally administered GAL (2.5 mg/kg) via oral gavage once daily for 15 days. The combination group (DOX + GAL) received GAL (once daily) and DOX (two times per week) concurrently. The body weights and survival rates were monitored daily. The animals were subjected to behavioral tests to assess the memory function followed by the biochemical estimation of inflammatory markers, including tumor necrosis factor-α (TNF-α), interleukine-1β (IL-1β), and interleukine-6 (IL-6) in rat brain tissue and RT-qPCR.

KEY FINDINGS

DOX caused a reduction in the body weight and survival rate, which was alleviated by GAL concomitant treatment with DOX (DOX + GAL). These groups had reduced body weights and survival rates. DOX-treated animals exhibited an impairment of short-term spatial working memory, manifested as a behavioral alteration in the Y-maze test, the novel object recognition (NOR) test, and the elevated plus-maze (EPM) test. Concurrent treatment with GAL (DOX + GAL) showed improved memory function, as evidenced by an increase in the number of entries and time spent in the novel arm, the time spent exploring the novel object, and the transfer latency in the Y-maze, NOR test, and EPM test, respectively. These findings were also supported by biochemical observations showing the reversal of DOX-induced changes in IL-1β, IL-6, and TNF-α, as well as their relative expression of mRNA in brain tissue following concurrent GAL treatment.

CONCLUSION

GAL appeared to be a neuroprotective agent against neuroinflammation caused by DOX by reducing inflammatory markers in the brain.

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.

The effects of endurance exercise and metformin on memory impairment caused by diabetes

OBJECTIVES

Diabetes has a negative effect on learning and memory performance, and it is a risk factor for Alzheimer's disease and dementia development. The present study aims to investigate the effects of two kinds of endurance exercise including high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) as well as metformin on impaired memory and learning related to streptozotocin (STZ) induced diabetes in rats.

METHODS

Forty adult male rats (250 ± 20 g weight) were divided into five groups (n=8), including control, diabetic, as well as diabetic rats treated with metformin (300 mg/kg), and HIIT (20 m/min), and MICT (15 m/min) exercises. Diabetes was induced by STZ (60 mg/kg, i.p.). Serum glucose concentration and oxidative stress markers (SOD, CAT, thiol, and MDA) in the cortex and hippocampus were determined by colorimetric assay. Behavioral tests were performed with a passive avoidance test.

RESULTS

The diabetic groups treated with metformin and both HIIT, and MICT exercises improved the latency and the staying time in the darkroom and lightroom. The entrance frequency into the darkroom also was restored (p<0.01-p<0.001). In both HIIT and MICT exercises as well as metformin groups the oxidative stress induced by diabetes has been reversed and attenuation of the serum glucose level has been observed compared to non-treated diabetic ones (p<0.05-p<0.001).

CONCLUSIONS

The results of the present study revealed both HIIT and MICT exercises had protective effects against oxidative stress and behavioral impairments induced by diabetes and these effects were comparable to the effects of metformin.

Effect of Various Intermittent Fasting Protocols on Hyperglycemia-Induced Cognitive Dysfunction in Rats

Diabetes mellitus is a highly prevalent metabolic disorder that causes cognitive decline. Here, we investigated the impact of various intermittent fasting protocols on type 2 diabetes mellitus (T2DM)-induced cognitive dysfunction in a rodent model. Male Sprague-Dawley rats (aged 3 months) were randomly assigned to five groups (n = 6 per group) and T2DM was induced by streptozotocin (60 mg/kg, IM). The control group was untreated. Cognitive function was tested (Y-maze, novel object recognition, and elevated plus maze tests) and glucose was assessed. The T2DM rats exhibited significantly higher blood glucose, which is associated with cognitive dysfunction. Compared to the validated animal model of T2DM in rats, various intermittent fasting protocols decreased blood glucose and improved cognitive function. These results indicate that various intermittent fasting protocols may be a potential strategy for managing the hyperglycemia-associated cognitive dysfunction.

Synergistic effect of metformin and doxorubicin on the metastatic potential of T24 cells

BACKGROUND

The motor ability of cancer cells to cross the basement membrane contributes to their implantation in a new location. Metastasis is a significant factor that worsens the prognosis of cancer patients. Thus, reducing cell invasiveness is an important aspect of anticancer therapy, also in bladder cancer treatment.

MATERIAL

The study material was the T24 cell line of human urinary bladder cancer. The migratory potential of the cells and the effect of the treatment with individually doses and synergistic combination of doxorubicin and metformin in the 500:1 ratio for 24 h were analyzed.

RESULTS

The results obtained show a compound-initiated decrease in the motor abilities of bladder cancer cells compared to controls. A decrease in the rate of colony formation was observed, as well as inhibition of migration through inserts. The visualized reorganization of the vimentin and actin networks confirms the drug-initiated limitation of the metastatic potential of T24 cells.

CONCLUSION

According to our knowledge, we are the first to show, that combination of doxorubicin and metformin also worth considering in the treatment of bladder cancer. We showed that simultaneous administration of these cytostatic enhances the antiproliferative effect of drugs, but also limits cells' migratory potential.

Mechanisms Underlying Cognitive Impairment Induced by Prenatal Alcohol Exposure

Alcohol is one of the most commonly used illicit substances among pregnant women. Clinical and experimental studies have revealed that prenatal alcohol exposure affects fetal brain development and ultimately results in the persistent impairment of the offspring's cognitive functions. Despite this, the rate of alcohol use among pregnant women has been progressively increasing. Various aspects of human and animal behavior, including learning and memory, are dependent on complex interactions between multiple mechanisms, such as receptor function, mitochondrial function, and protein kinase activation, which are especially vulnerable to alterations during the developmental period. Thus, the exploration of the mechanisms that are altered in response to prenatal alcohol exposure is necessary to develop an understanding of how homeostatic imbalance and various long-term neurobehavioral impairments manifest following alcohol abuse during pregnancy. There is evidence that prenatal alcohol exposure results in vast alterations in mechanisms such as long-term potentiation, mitochondrial function, and protein kinase activation in the brain of offspring. However, to the best of our knowledge, there are very few recent reviews that focus on the cognitive effects of prenatal alcohol exposure and the associated mechanisms. Therefore, in this review, we aim to provide a comprehensive summary of the recently reported alterations to various mechanisms following alcohol exposure during pregnancy, and to draw potential associations with behavioral changes in affected offspring.

Statins and Left Ventricular Ejection Fraction Following Doxorubicin Treatment

BACKGROUND

Statins taken for cardiovascular indications by patients with breast cancer and lymphoma during doxorubicin treatment may attenuate left ventricular ejection fraction (LVEF) decline, but the effect of statins on LVEF among patients with no cardiovascular indications is unknown.

METHODS

A double-blind, placebo-controlled, 24-month randomized trial of 40 mg of atorvastatin per day administered to patients with breast cancer and lymphoma receiving doxorubicin was conducted within the National Cancer Institute Community Oncology Research Program across 31 sites in the United States. At pretreatment and then 6 and 24 months after initiating doxorubicin, we assessed left ventricular (LV) volumes, strain, mass, and LVEF through cardiac magnetic resonance imaging, along with cognitive function and serum markers of inflammation. The primary outcome was the difference in 24-month LVEF between placebo and treatment groups, adjusted for pretreatment LVEF.

RESULTS

A total of 279 participants were enrolled in the trial. Participants had a mean (±SD) age of 49±12 years; 92% were women; and 83% were White. The mean (±SD) LVEF values were 61.7±5.5% before treatment and 57.4±6.8% at 24 months in the placebo group and 62.6±6.4% before treatment and 57.7±5.6% at 24 months in the atorvastatin group. On the basis of a multiple imputed data set for missing data and adjusted for each individual's pretreatment LVEF, 24-month declines in LVEF averaged 3.3±0.6 percentage points and 3.2±0.7 percentage points, for those randomly assigned to placebo versus statins, respectively (P=0.93). Across both treatment arms, similar percentages of individuals experienced changes of more than 10 percentage points in LVEF, LV strain, LV mass, cognition, and inflammation biomarkers, including among those with greater than 90% drug compliance.

CONCLUSIONS

In patients with breast cancer and lymphoma with no existing indication for statin therapy, prospective statin administration did not affect LVEF declines 2 years after doxorubicin. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01988571.).

Infliximab and/or MESNA alleviate doxorubicin-induced Alzheimer's disease-like pathology in rats: A new insight into TNF-α/Wnt/β-catenin signaling pathway

AIMS

The current study aimed to elucidate the neurotoxic potential of DOX to induce AD-like pathology paying attention to the role of wingless-integrated/β-catenin (Wnt/β-catenin) signaling pathway. A major aim was to evaluate the efficacy of infliximab (IFX) either individually or in combination with 2-mercaptoethane sulfonate sodium (MESNA) on the DOX-induced neurotoxicity in rats.

METHODOLOGY

AD-like pathology was induced in adult male Wistar rats by intraperitoneal (i.p.) administration of DOX at a dose of 3.5 mg/kg twice a week for 3 weeks. DOX-injected rats were then treated with either INF at a single dose of 5 mg/kg i.p. (IFX group), MESNA at a dose of 160 mg/kg/day i.p. for 4 weeks (MESNA group) or their combination at the same specified doses (INF + MESNA group). At the end of the study period, behavioral assessment was performed and the brain tissue samples were harvested at sacrifice.

KEY FINDINGS

DOX-treated rats significantly exhibited AD-like brain injury, increased amyloid burden, enhanced neuroinflammation and apoptosis, and multifocal histological injury in the cerebral cortex with widespread vacuolations. IFX and MESNA significantly reversed all the aforementioned detrimental effects in the DOX-treated rats.

SIGNIFICANCE

The study has provided sufficient evidence of the potential of IFX and/or MESNA to ameliorate the DOX-induced neurotoxicity, with the best improvement observed with their combined administration. A new insight has been introduced into the critical role of Wnt/β-catenin activation.

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

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

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Biochemical and histological alterations of doxorubicin-induced neurotoxicity in rats: Protective role of luteolin

Doxorubicin (DOX) is a chemotherapeutic drug used in the treatment of various cancer types. DOX toxic side effects include neuronopathy and memory deficits. We investigated the effect of the antioxidant luteolin (LUT: 50 or 100 mg/kg; per os) on DOX (2 mg/kg; intraperitoneal)-induced oxidative stress (OS), inflammation, and apoptosis in the brain of Wistar rats for 14 days. We observed that LUT reduced DOX-mediated increase in OS biomarkers-catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase. LUT increased glutathione and total sulphydryl levels and alleviated DOX-induced increases in the levels of reactive oxygen and nitrogen species, lipid peroxidation, myeloperoxidase, nitric oxide, tumor necrosis factor-α, and interleukin-1β (IL-1β). Additionally, LUT suppressed caspase-3 activity, increased anti-inflammatory cytokine-IL-10 level, and reduced pathological lesions in the examined organs of rats cotreated with LUT and DOX. Collectively, cotreatment with LUT lessened DOX-induced neurotoxicity. Supplementation of LUT as a chemopreventive agent might be useful in patients undergoing DOX chemotherapy.

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.

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.

Neuropathological Effects of Chemotherapeutic Drugs

Novel treatments, screening, and detection methods have prolonged the lives of numerous cancer patients worldwide. Unfortunately, existing and many promising new chemotherapeutics can cause deleterious, off-target side effects in normal tissue and organ systems. The central and peripheral nervous systems are widely recognized as frequent off-target effectors of anticancer drugs which can produce persistent neurological and neuropsychiatric symptoms collectively termed "chemobrain". Following chemotherapy, patients report several forms of cognitive impairment occurring acutely and sometimes persisting years after treatment. There are no effective treatments for cognitive decline induced by chemotherapeutics, and the underlying molecular mechanisms are poorly characterized and understood. In this study, we find that chronic treatment with two common chemotherapeutic agents, cisplatin and gemcitabine, impairs brain region-specific metabolism, hippocampus-dependent memory formation, and stress response behavior. This corresponds to reduced hippocampal synaptic excitability, altered neuronal signal transduction, and neuroinflammation. These findings underline that a better understanding of the basic pathological consequences of chemotherapy-induced cognitive impairment is the first step toward improving cancer treatment survivorship.