Pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, is known to have anti-inflammatory and anti-oxidant effects on the brain, and its clinical potential in the treatment of cognitive impairment in diseases such as Alzheimer’s disease (AD) and Parkinson disease (PD) is currently being explored. This review focused on the reported beneficial effects of pioglitazone on cognitive dysfunction and summarized the associated mechanisms associated with pioglitazone-induced improvement in cognitive dysfunction. Our review of the relevant literature indicated that there is conclusive evidence of the effect of pioglitazone on improving cognitive impairment via its agonistic effect on PPAR-γ. Further, several mechanisms of action have been reported, and these include enhanced NF-kB and p38 activity; regulation of the pro-inflammatory cytokines IL-1, IL-6, and TNF-α; inhibition of Aβ production; alterations in the levels of mitochondrial proteins such as mitoNEET; regulation of protein kinases such as CDK5 and JNK; regulation of ROS and MDA levels and the levels of the antioxidant proteins TRX1 and PON2; and increased expression of thyroid hormone receptors. Despite these promising findings, pioglitazone treatment is also associated with cardiovascular risks, such as weight gain and edema, which subsequently increase the risk of mortality. Further, it has been documented that pioglitazone may be unable to cross the blood–brain barrier when administered in certain forms, and it can also cause cell death when administered at high concentrations. Therefore, further research is required to explore the effects of acute and chronic pioglitazone treatment on memory function and the associated risks, in order to determine its clinical applicability in the treatment of cognitive disorders. Nonetheless, the current literature does demonstrate that pioglitazone promotes the function of PPAR receptors in ameliorating inflammation, oxidative stress, amyloidogenesis, and hypothyroidism, and enhancing neurogenesis, synaptic plasticity, and mitochondrial function. Therefore, these mechanisms of PPAR receptors warrant further investigation in order to establish the clinical applicability of pioglitazone in the treatment of cognitive disorders, such as PD and AD, and neuronal impairment in conditions such as diabetes.

The health risks of nicotine are well known, but there is some evidence of its beneficial effects on cognitive function. The present review focused on the reported benefits of nicotine in the brain and summarizes the associated underlying mechanisms. Nicotine administration can improve cognitive impairment in Alzheimer's disease (AD), and dyskinesia and memory impairment in Parkinson's disease (PD). In terms of its mechanism of action, nicotine slows the progression of PD by inhibiting Sirtuin 6, a stress‑responsive protein deacetylase, thereby decreasing neuronal apoptosis and improving neuronal survival. In AD, nicotine improves cognitive impairment by enhancing protein kinase B (also referred to as Akt) activity and stimulating phosphoinositide 3‑kinase/Akt signaling, which regulates learning and memory processes. Nicotine may also activate thyroid receptor signaling pathways to improve memory impairment caused by hypothyroidism. In healthy individuals, nicotine improves memory impairment caused by sleep deprivation by enhancing the phosphorylation of calmodulin‑dependent protein kinase II, an essential regulator of cell proliferation and synaptic plasticity. Furthermore, nicotine may improve memory function through its effect on chromatin modification via the inhibition of histone deacetylases, which causes transcriptional changes in memory‑related genes. Finally, nicotine administration has been demonstrated to rescue long‑term potentiation in individuals with sleep deprivation, AD, chronic stress and hypothyroidism, primarily by desensitizing α7 nicotinic acetylcholine receptors. To conclude, nicotine has several cognitive benefits in healthy individuals, as well as in those with cognitive dysfunction associated with various diseases. However, further research is required to shed light on the effect of acute and chronic nicotine treatment on memory function.

Background: The nuclear factor kappa-B (NF-κB) is a major transcription factor responsible for the production of numerous inflammatory mediators, including the tumor necrosis factor (TNFα), which has a lethal association with cancer’s onset. The silver nanoparticles (AgNPs) are widely used in cancer treatment and several other biomedical applications. Objective: The study aimed to determine the effects of silver citrate nanoparticles (AgNPs-CIT) on NF-κB activation together with TNFα mRNA/protein expressions in the phorbol myristate acetate (PMA)-stimulated MCF-7 human breast cancer cell-lines. Methods: The AgNPs-CIT were synthesized by the reduction method, and the prepared AgNPs-CIT were characterized for their shape, absorption in UV-VIS electromagnetic radiations, size distribution, ζ-potential, and antioxidant activity. The MCF-7 cell-lines were pretreated with AgNPs-CIT and stimulated with PMA. The TNFα mRNA expressions were determined by real-time PCR, whereas the protein production was determined by the ELISA. The NF-κB activity was distinctly observed by highly-specific DNA-based ELISA, and by NF-κB-specific inhibitor, Bay 11– 7082. Results: The prepared AgNPs-CIT were spherical and have an absorption wavelength range of 381– 452 nm wherein the particles size ranged between 19.2± 0.1 to 220.77± 0.12 nm with the charge range − 9.99± 0.8 to − 34.63± 0.1 mV. The prepared AgNPs-CIT showed comparative antioxidant activity at > 40% inhibitions level of the DPPH radicals. The AgNPs-CIT were found to be non-toxic to MCF-7 cell-lines and inhibited PMA-induced activation of the NF-κBp65, and also the mRNA/protein expression of TNFα. Conclusion: This is the first report that showed AgNPs-CIT inhibited TNFα expression via deactivation of the NF-κB signaling event in stimulated breast cancer cells. The results have important implications for the development of novel therapeutic strategies for the prevention/treatment of cancers and/or inflammatory disorders.

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.

Methotrexate (MTX; 4-amino-10-methylfolic acid) is a folic acid reductase inhibitor used to treat autoimmune diseases and certain types of cancer. Testicular toxicity resulting from MTX is a significant side effect that may cause subsequent infertility. The present study was conducted to examine the ameliorating effects of vitamin B17 (VitB17) against testicular toxicity induced by MTX in male rats. A total of 50 male albino rats were equally divided into five groups [control group; vitamin B17 group (VitB17) administered VitB17 only; methotrexate group administered MTX only; cotreated group, (VitB17+MTX) and posttreated group (MTX+VitB17)]. In methotrexate group (MTX), a significant decrease was observed in body weight and the testicular weight, as well as the levels of plasma testosterone, luteinizing hormone and follicle-stimulating hormone compared with control. The sperm count, viability, morphology index, total motility, and progressive motility also decreased in MTX rats compared with control. Furthermore, the levels of reduced glutathione, catalase, and superoxide dismutase, as well as proliferating cell nuclear antigen protein expression, in the testicular tissue decreased in MTX compared with control. In addition, MTX caused a significant increase in DNA and tissue damage compared with control. However, VitB17 ameliorated these effects, indicating that it has a preventative and curative effect against MTX-induced reproductive toxicity in male rats. The protective effect of VitB17 may be associated to its antioxidant properties as it possibly acts as a free-radical scavenger and lipid peroxidation inhibitor, as well as its protective effect on the levels of GSH, SOD, and CAT.

Background: This study is designed to discover a method for delivering an efficient potent pheophytin a (pheo-a) into more absorbed and small polymeric ethyl cellulose (EC) microparticles. Methods: Silica gel and Sephadex LH-20 columns were used to isolate pheo-a from the chloroform extract of the edible plant, Suaeda vermiculata. Pheo-a was incorporated into EC microparticles using emulsion-solvent techniques. The antioxidant activity of pheo-a microparticles was confirmed by the level of superoxide radical (SOD), nitric oxide (NO), and reducing power (RP) methods. Meanwhile, the cytotoxic effect of the product was investigated on MCF-7 cells using MTT assay. Results: Pheo-a was isolated from S. vermiculata in a 12% concentration of the total chloroform extract. The structures were confirmed by NMR and IR spectroscopic analysis. The formulated microparticles were uniform, completely dispersed in the aqueous media, compatible as ingredients, and had a mean diameter of 139 ± 1.56 µm as measured by a particle size analyzer. Pheo-a demonstrated a valuable antioxidant activity when compared with ascorbic acid. The IC₅₀ values of pheo-a microparticles were 200.5 and 137.7 µg/mL for SOD, and NO respectively. The reducing power of pheo-a microparticles was more potent than ascorbic acid and had a 4.2 µg/mL for IC₅₀ value. Pheo-a microparticles did not show notable cytotoxicity on the MCF-7 cell line (IC₅₀ = 35.9 µg/mL) compared with doxorubicin (IC₅₀ = 3.2 µg/mL). Conclusions: the results showed that water-soluble pheo-a microparticles were prepared with a valuable antioxidant activity in a wide range of concentrations with a noteworthy cytotoxic effect.