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Recent studies have suggested that irisin may act as a potential neurokine. Exercise and L-carnosine supplementation showed neuroprotective effects in Alzheimer's disease (AD)-like conditions. However, the regulation of irisin in the hippocampus of streptozotocin (STZ)-induced memory impairment and its relation to insulin signalling remain to be investigated. This study was designed to compare the effect of swimming exercise and L-carnosine intake on serum, CSF and hippocampal irisin in rats received intracerebroventricular (ICV) injection of STZ. Rats were recruited in swimming paradigm, received oral carnosine (100 mg/kg/day) or vehicle treated. After 5 weeks, rats were sacrificed after neurobehavioural testing. CSF and serum irisin were determined. Hippocampal tissues were used to assess expression of FNDC5/irisin, BDNF and proteins related to insulin signalling, in addition to β-amyloid peptide and phosphorylated tau protein levels. We observed decreased hippocampal, but not CSF or serum, irisin in ICV-STZ-injected rats. Exercise and carnosine intake almost normalized hippocampal FNDC5/irisin expression which was associated with reduced soluble β-amyloid peptide and phosphorylated tau protein, improved BDNF and insulin signalling proteins, with corresponding mitigated cognitive impairments. However, hippocampal FNDC5/irisin was not correlated with serum or CSF irisin levels. Histologically, both interventions ameliorated the hippocampal damage in STZ-injected rats. The current study reveals that carnosine is equivalent to exercise in reversing cognitive decline and Alzheimer's biomarkers. In both interventions, enhancement of hippocampal FNDC5/irisin and insulin signalling may be involved in mediating these neuroprotective effects., (© 2021. University of Navarra.)

Alzheimer's disease (AD) is neurological disorder characterized by dementia which causes severe problems with behavior, thinking and memory. Systemic administration of therapeutics to the central nervous system (CNS) is usually associated with very low efficiency due to presence of blood brain barrier (BBB), which only allows permeation of few types of molecules from the circulation to the CNS. As an alternative, naturally amphiphilic micelles can be utilized to enhance targeted drug delivery to the brain. In this sense, lactoferrin (LF) was covalently attached to conjugated linoleic acid (CLA) via carbodiimide coupling reaction to form a new micellar nanoplatform with particle size of about 53 nm. Afterwards, fabricated micelles were further loaded once again with CLA to enhance its delivery to the CNS. In vitro drug release study revealed that CLA exhibited sustained release at pH 6.8, associated with good hemocompatibility without any remarkable in vivo toxicity in terms of liver and kidney functions. Moreover, in vivo studies showed that the fabricated micelles manifested enhanced in vivo biodistrbution in brain tissue due to the active targeting potential of LF. Additionally, drug-loaded LF-CLA micelles exhibited enhanced cognitive capabilities, reduced brain oxidative stress, inflammation, apoptosis and acetylcholine esterase activity, besides a decline in the deposition of amyloid β peptide1-42 in aluminum chloride Alzheimer's-induced animal model. CLA-based micelles could be a promising CNS actively targeted delivery system with a sophisticated potential to reduce AD symptoms., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Alzheimer's disease (AD) is a neurodegenerative disorder that has no cure till now. Piperine (PIP) is an alkaloid characterized by memory-enhancing properties but challenging oral delivery obstacles. The objectives of this study are as follows: preparation of microemulsion (ME) as a proposed oral PIP nanocarrier for treatment of Alzheimer's disease and testing its safety on the brain and other internal organs. This study employs bioactive surfactants in the common safe doses to improve PIP targeting to the brain. Selected ME systems encompassed Caproyl 90 (oil)/Tween 80/Cremophor RH 40 (surfactant) and Transcutol HP (co-surfactant). The particle size of the prepared formulations was less than 150 nm with negative zeta potential. The in vivo results showed a superior effect of ME over free PIP. Colchicine-induced brain toxicity results showed the safety of ME on brain cells. Nevertheless, toxicological results showed a potential ME nephrotoxicity. Oral microemulsion increased PIP efficacy and enhanced its delivery to the brain resulting in better therapeutic outcome compared to the free drug. However, the toxicity of this nanosystem should be carefully taken into consideration on chronic use.

Piperine (PIP) is a phytopharmaceutical with reported neuroprotective potential in Alzheimer's disease (AD). Oral PIP delivery suffers from its hydrophobicity and pre-systemic metabolism. In this article, mono-disperse intranasal chitosan nanoparticles (CS-NPs) were elaborated for brain targeting of PIP. Formula optimization was based on particle size (PS), zeta potential (ZP), polydispersity index (PDI), % entrapment efficiency (% EE), release studies, and transmission electron microscopy. AD was induced in 48 male Wistar rats on which full behavioral and biochemical testing was conducted. Brain toxicity was assessed based on Caspase-3 assay for apoptosis and tumor necrosis factor for inflammation. Spherical NPs with optimum % EE (81.70), PS (248.50 nm), PDI (0.24), and ZP (+56.30 mV) were elaborated. PIP-NPs could significantly improve cognitive functions as efficient as standard drug (donpezil injection) with additional advantages of dual mechanism (Ach esterase inhibition and antioxidant effect). CS-NPs could significantly alleviate PIP nasal irritation and showed no brain toxicity. This work was the first to report additional mechanism of PIP in AD via anti-apoptosis and anti-inflammatory effects. To conclude, mucoadhesive CS-NPs were successfully tailored for effective, safe, and non-invasive PIP delivery with 20-folds decrease in oral dose, opening a gate for a future with lower AD morbidity., (© 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.)

Alzheimer's disease (AD) is one of the most patient devastating central nervous system diseases with no curative therapy. An effective oral therapy with brain-targeting potential is required that is hampered by blood-brain barrier. Piperine (PIP) is a natural alkaloid with memory enhancing potentials. Oral PIP delivery suffers from its hydrophobicity and first-pass metabolism. In this study, novel Tween-modified monoolein cubosomes (T-cubs) were elaborated as bioactive nanocarriers for brain-targeted oral delivery of PIP. Seven liquid crystalline nanoparticles (cubosomes) were prepared testing different bioactive surfactants (Tween 80, poloxamer, and Cremophor). Full in vitro characterization was carried out based on particle size, zeta potential, polydispersity index, entrapment efficiency, and in vitro release. Morphological examination and structure elucidation were performed using transmission and polarizing microscopes. Sporadic dementia of Alzheimer's type was induced in 42 male Wistar rats on which full behavioral and biochemical testing was conducted. Brain toxicity was assessed based on Caspase-3 assay for apoptosis and tumor necrosis factor-α for inflammation. Liver and kidney toxicity studies were conducted as well. Among others, T-cubs exhibited optimum particle size (167.00±10.49 nm), polydispersity index (0.18±0.01), and zeta potential (-34.60±0.47 mv) with high entrapment efficiency (86.67%±0.62%). Cubs could significantly sustain PIP in vitro release. In vivo studies revealed T-cubs potential to significantly enhance PIP cognitive effect and even restore cognitive function to the normal level. Superiority of T-cubs over others suggested brain-targeting effect of Tween. Toxicological studies contended safety of cubs on kidney, liver, and even brain. T-cubs exhibited potential anti-inflammatory and anti-apoptotic activity of loaded PIP, indicating potential to stop AD progression that was first suggested in this article. Novel oral nanoparticles elaborated possess promising in vitro and in vivo characteristics with high safety for effective chronic treatment of AD.