The effect of baicalein-loaded Y-shaped miktoarm copolymer on spatial memory and hippocampal expression of DHCR24, SELADIN and SIRT6 genes in rat model of Alzheimer

Regulation of neuroinflammation in Alzheimer's disease via nanoparticle-loaded phytocompounds with anti-inflammatory and autophagy-inducing properties

BACKGROUND

Alzheimer's disease (AD) is characterized by neuroinflammation linked to amyloid β (Aβ) aggregation and phosphorylated tau (τ) protein in neurofibrillary tangles (NFTs). Key elements in Aβ production and NFT assembly, like γ-secretase and p38 mitogen-activated protein kinase (p38MAPK), contribute to neuroinflammation. In addition, impaired proteosomal and autophagic pathways increase Aβ and τ aggregation, leading to neuronal damage. Conventional neuroinflammation drugs have limitations due to unidirectional therapeutic approaches and challenges in crossing the Blood-Brain Barrier (BBB). Clinical trials for non-steroidal anti-inflammatory drugs (NSAIDs) and other therapeutics remain uncertain. Novel strategies addressing the complex pathogenesis and BBB translocation are needed to effectively tackle AD-related neuroinflammation.

PURPOSE

The current scenario demands for a much-sophisticated theranostic measures which could be achieved via customized engineering and designing of novel nanotherapeutics. As, these therapeutics functions as a double edge sword, having the efficiency of unambiguous targeting, multiple drug delivery and ability to cross BBB proficiently.

METHODS

Inclusion criteria involve selecting recent, English-language studies from the past decade (2013-2023) that explore the regulation of neuroinflammation in neuroinflammation, Alzheimer's disease, amyloid β, tau protein, nanoparticles, autophagy, and phytocompounds. Various study types, including clinical trials, experiments, and reviews, were considered. Exclusion criteria comprised non-relevant publication types, studies unrelated to Alzheimer's disease or phytocompounds, those with methodological flaws, duplicates, and studies with inaccessible data.

RESULTS

In this study, polymeric nanoparticles loaded with specific phytocompounds and coated with an antibody targeting the transferrin receptor (anti-TfR) present on BBB. Thereafter, the engineered nanoparticles with the ability to efficiently traverse the BBB and interact with target molecules within the brain, could induce autophagy, a cellular process crucial for neuronal health, and exhibit potent anti-inflammatory effects. Henceforth, the proposed combination of desired phytocompounds, polymeric nanoparticles, and anti-TfR coating presents a promising approach for targeted drug delivery to the brain, with potential implications in neuroinflammatory conditions such as Alzheimer's disease.

Valine conjugated polymeric nanocarriers for targeted co-delivery of rivastigmine and quercetin in rat model of Alzheimer disease

Multifunctional nanocarriers are increasingly promising for disease treatment aimed at finding effective therapy and overcoming barriers in drug delivery. Herein, valine conjugated chitosan (VLCS) was used for surface modification of nanocarriers (NCs) based on Poly (ε-caprolactone)-Poly (ethylene glycol)-Poly (ε-caprolactone) (PCL-PEG-PCL) triblock copolymers (NCs@VLCS). The nanocarriers were co-loaded with rivastigmine (RV) and quercetin (QT) to yield the final RV/QT-NCs@VLCS as a multifunctional nanocarrier for Alzheimer's disease (AD) treatment. The large amino acid transporter 1 (LAT-1) was selected for the direction of the NCs to the brain. The biocompatibility of the nanocarrier was studied in HEK-293 and SH-SY5Y cells and rats. The Morris water maze test demonstrated a faster regain of memory loss with RV/QT-NCs@VLCS compared to the other groups. Furthermore, RV/QT-NCs@VLCS and RV/QT-NCs improved GSH depletion induced by scopolamine (SCO), with RV/QT-NCs@VLCS having a superior effect. The real-time PCR analysis revealed that co-delivery of RV and QT by NCs@VLCS showed significantly higher efficacy than sole delivery of RV. RV/QT-NCs@VLCS treatment also modulated the expression of BDNF, ACHE, and TNF-α. The findings revealed that NCs@VLCS co-loaded with RV and QT, significantly increased efficacy relative to the single use of RV and could be considered a potent multifunctional drug delivery system for Alzheimer's treatment.

Chronic treatment with baicalein alleviates behavioural disorders and improves cerebral blood flow via reverting metabolic abnormalities in a J20 transgenic mouse model of Alzheimer's disease

Baicalein (BE) has both antioxidant and anti-inflammatory effects. It has also been reported able to improve cerebral blood circulation in brain ischemic injury. However, its chronic efficacy and metabolomics in Alzheimer's disease (AD) remain unknown. In this study, BE at 80 mg/kg was administrated through the oral route in J20 AD transgenic mice aged from aged 4 months to aged 10 months. Metabolic- and neurobehavioural phenotyping was done before and after 6 months' treatment to evaluate the drug efficacy and the relevant mechanisms. Meanwhile, molecular docking was used to study the binding affinity of BE and poly (ADP-ribose) polymerase-1 (PARP-1) which is related to neuronal injury. The open field test showed that BE could suppress hyperactivity in J20 mice and increase the frequency of the target quadrant crossing in the Morris Water Maze test. More importantly, BE restored cerebral blood flow back to the normal level after the chronic treatment. A ¹H NMR-based metabolomics study showed that BE treatment could restore the tricarboxylic acid cycle in plasma. And such a treatment could suppress oxidative stress, inhibit neuroinflammation, alleviate mitochondrial dysfunction, improve neurotransmission, and restore amino homeostasis via starch and sucrose metabolism and glycolipid metabolism in the cortex and hippocampus, which could affect the behavioural and cerebral blood flow. These findings showed that BE is a potential therapeutic agent for AD.

Hospital wastewater treatment using eco-friendly eugenol nanostructured lipid carriers: Formulation, optimization, and in vitro study for antibacterial and antioxidant properties

In this study, nano-formulation has been used to tackle one of the most important environmental problems which can be considered a major threat to human health. We prepared some eco-friendly nanostructured lipid carriers (NLCs) as delivery agents to properly deliver an antibacterial agent (eugenol) into hospital wastewater in order to control bacterial growth. Eugenol-loaded nanostructured lipid carriers were prepared by hot high-speed homogenization. Then, the prepared nanocarriers were characterized using different techniques such as transmission electron microscopy, Fourier transform infrared, and dynamic scanning calorimetry. The turbidity assay and colony counting method were used to determine the ability of the prepared eugenol-loaded nanostructured lipid carriers to inhibit bacterial growth rate in the culture media and hospital wastewater, respectively. The mean size and zeta potential of NLC-eugenol were 78.12 ± 6.1 nm and -29.43 ± 2.21 mV, respectively. The results showed that the highest inhibitory effect of NLC-eugenol in culture media was seen in standard and wild Staphylococcus aureus strains (43.42% and 26.41%, respectively) with a concentration of 0.125 μM. The antibacterial activity of NLC-eugenol in sterile wastewater on wild strains of bacteria showed that the most effective concentration to reduce bacterial amounts was 0.125 μM on wild S. aureus and Enterococcus faecalis strains (38% and 33.47%, respectively) at 37°C. The NLC-eugenol with a concentration of 0.125 μM showed the greatest effect of reducing total microbial agents by 28.66% in hospital wastewater at 25°C. The highest antibacterial effect achieved using the 0.125 μM concentration is due to the egel phenomenon. Also, the mechanism of action of NLC-eugenol is cell wall destruction and eventually cell death. The results showed that NLC-eugenol with a concentration of 0.125 μM can reduce wild bacterial strains in sterilized wastewater and hospital wastewater, which can prove the great potential of the prepared eugenol-loaded nanostructured lipid carriers to control bacterial growth. PRACTITIONER POINTS: NLC is one of the safest biodegradable and environmentally friendly carriers, which is nontoxic for humans and the environment. Eugenol is a natural compound, which makes it less toxic for the environment while being toxic for bacteria. Therefore, our method has the least side effect in comparison with existing methods for wastewater treatment. The gradual release of eugenol from NLC nanoparticles can effectively control the pathogenic factors of wastewater.

Clavulanic Acid: A Novel Potential Agent in Prevention and Treatment of Scopolamine-Induced Alzheimer's Disease

Background and Aim: Alzheimer's disease (AD) is the most common form of dementia in the elderly. It is characterized as a multifaced disorder with a greater genetic contribution. The contribution of many genes such as BDNF, Sirtuin 6, and Seladin 1 has been reported in the pathogenesis of AD. Current therapies include acetylcholinesterase inhibitors and N-methyl-d-aspartate receptor antagonists, which are only temporarily beneficial. Therefore, it seems that more studies should be conducted to determine the exact mechanisms of drugs to deal with the diseases' multifactorial features that we face. Methods: In this study, 42 adult rats were randomly divided into 7 groups and received drugs intraperitoneally and orally according to the protocol as follows: scopolamine group, clavulanic acid group, memantine group, scopolamine + memantine group, clavulanic acid pre- and post-treatment, and normal saline group. The Morris water maze method was performed to evaluate the spatial memory of animals, and the terminal deoxynucleotidyl transferase dUTP nick end labeling assay and real-time polymerase chain reaction were performed to study neuronal cell apoptosis and gene expression, respectively. Results: Significant differences were observed in the spatial memory of rats that received clavulanic acid prophylactically compared to the Alzheimer's model on the day of the test. Moreover, the results obtained during the training showed that both memantine and clavulanic acid improved spatial memory by increasing the time of rats present in the platform position and by reducing the swimming time in the scopolamine-induced Alzheimer's group. Besides, rats that received clavulanic acid and memantine had a greater percentage of healthy cells in comparison with the scopolamine-induced Alzheimer's group; however, the results were more significant for clavulanic acid. Furthermore, the expressions of BDNF, Seladin 1, and Sirtuin 6 as neuroprotective target genes were modified after clavulanic acid and memantine administrations; similarly, the results obtained from clavulanic acid were more significant. Conclusion: The results show that the administration of clavulanic acid before and after the use of scopolamine can reduce the percentage of apoptotic cells in the hippocampus and also improve the parameters related to learning and spatial memory; however, its effect in the prophylactic state was stronger. The results obtained from memantine revealed that it has neuroprotective potency against AD; however, clavulanic acid had a greater effect. Also, with increased expression of the neuroprotective genes, clavulanic acid could be considered as an option in the upcoming preclinical and clinical research about Alzheimer's disease.

Carnosine improves cognitive impairment through promoting SIRT6 expression and inhibiting ER stress in a diabetic encephalopathy model

Diabetic encephalopathy is one of complications of diabetes mellitus. Carnosine is a dipeptide composed of β-alanine and L-histidine. Study has shown that carnosine could ameliorate cognitive impairment in animal model with diabetes mellitus. However, the mechanism remains unclear. An animal model of type 2 diabetes (db/db mice) was used in this study. The animals were treated with 0.9 % saline or carnosine (100 mg/kg) for 8 weeks. Morris water maze was tested after drug administration. Oxidative stress-related factors malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), and pro-inflammatory factors inducible nitric oxide synthase (iNOS) were measured. Synapse-related protein postsynapticdensity 95 (PSD95) and brain-derived neurotrophic factor (BDNF) were detected by western blot. Besides, the expressions of sirtuin 6 (SIRT6), binding immunoglobulin protein (BIP), protein kinase R-like endoplasmic reticulum kinase (PERK), phospho-protein kinase R-like endoplasmic reticulum kinase (P-PERK), inositol-requiring enzyme-1α (IRE1α), phospho-inositol-requiring enzyme-1α (P-IRE1α), activating transcription factor 6 (ATF6), C/EBP-homologous protein (CHOP) in the hippocampus of the brain were detected. The results showed that treatment with carnosine ameliorated cognitive impairment in db/db mice. Carnosine reduced neuronal oxidative stress damage and iNOS expression in db/db mice. Meanwhile, carnosine relieved neurodegeneration in the hippocampus of db/db mice. Furthermore, carnosine promoted the expression of SIRT6 and reduced the expressions of endoplasmic reticulum (ER) related factors (BIP, P-PERK, P-IRE1α, ATF6, CHOP). In conclusion, these data suggested that the protective effect of carnosine against diabetic encephalopathy might be related to SIRT6/ER stress pathway.

Synergic Antitumor Effect of Photodynamic Therapy and Chemotherapy Mediated by Nano Drug Delivery Systems

This review provides a summary of recent progress in the development of different nano-platforms for the efficient synergistic effect between photodynamic therapy and chemotherapy. In particular, this review focuses on various methods in which photosensitizers and chemotherapeutic agents are co-delivered to the targeted tumor site. In many cases, the photosensitizers act as drug carriers, but this review, also covers different types of appropriate nanocarriers that aid in the delivery of photosensitizers to the tumor site. These nanocarriers include transition metal, silica and graphene-based materials, liposomes, dendrimers, polymers, metal–organic frameworks, nano emulsions, and biologically derived nanocarriers. Many studies have demonstrated various benefits from using these nanocarriers including enhanced water solubility, stability, longer circulation times, and higher accumulation of therapeutic agents/photosensitizers at tumor sites. This review also describes novel approaches from different research groups that utilize various targeting strategies to increase treatment efficacy through simultaneous photodynamic therapy and chemotherapy.

Block copolymers in Alzheimer's disease therapy: A perceptive to revolutionize biomaterials

Alzheimer's disease is a fatal illness associated with two persistent problems in treatment i. ineffective drug transportation across the bio-membranes and ii. on-site targeting. Such problems originate from the combinational factors for non-specific targets, physicochemical limitations in the delivery of the active agents and insignificant permeability across blood-brain-barrier. In this context, block copolymers such as PLGA-PEG, PEG-PLA, Poloxamers, PLGA-PEG-PLGA triblock copolymers, etc. present interesting potential in the development of nano-sized carrier systems like polymerosomes, polymeric micelles, etc. for the management and treatment of Alzheimer's disease. Modifications of block copolymers display improvement in solubility and reduction in toxicity due to the process of complexation, functionalization, dose reduction and modification of kinetics for the rate of release. This review article focuses on new insights into different copolymers and their superiority over conventional polymers in Alzheimer's disease for long-term therapy in the body. Association of block copolymers to therapy of Alzheimer's disease overcome the limitations of drug delivery by offering attributes such as smaller molecular size (less than 150 nm), higher solubility owing to hydrophilic interactions between polymeric components and systemic environment, better entrapment efficiency (above 80%) due to large effective surface area and long-term stability for sensitive actives such as peptides, monoclonal antibodies, curcumin, resveratrol, catechins, etc. With such multifunctional features, block copolymers actively permeate the bio-membrane as polymeric nanoparticles, nanomicelles and polymerosomes using different mechanisms such as transcellular- and receptor-mediated transportation to reach target neural network as well as extra-neuronal amyloid-β plaques for anti-Alzheimer's disease activity with neuroprotective action. These polymers emerge as important components for personalized therapy with potential applications in biosensing, drug delivery, theranostics, etc. for qualitative and quantitative predictions in the detection and treatment of Alzheimer's disease.

Dual-Targeted Nanoplatform Regulating the Bone Immune Microenvironment Enhances Fracture Healing

The immune system and skeletal system are closely linked. Macrophages are one of the most important immune cells for bone remodeling, playing a prohealing role mainly through M2 phenotype polarization. Baicalein (5,6,7-trihydroxyflavone, BCL) has been well documented to have a noticeable promotion effect on M2 macrophage polarization. However, due to the limitations in targeted delivery to macrophages and the toxic effect on other organs, BCL has rarely been used in the treatment of bone fractures. In this study, we developed mesoporous silica and Fe₃O₄ composite-targeted nanoparticles loaded with BCL (BCL@MMSNPs-SS-CD-NW), which could be magnetically delivered to the fracture site. This induced macrophage recruitment in a targeted manner, polarizing them toward the M2 phenotype, which was demonstrated to induce mesenchymal stem cells (MSCs) toward osteoblastic differentiation. The mesoporous silicon nanoparticles (MSNs) were prepared with surface sulfhydrylation and amination modification, and the mesoporous channels were blocked with β-cyclodextrin. The outer layer of the mesoporous silicon was added with an amantane-modified NW-targeting peptide to obtain the targeted nanosystem. After entering macrophages, BCL could be released from nanoparticles since the disulfide linker could be cleaved by intracellular glutathione (GSH), resulting in the removal of cyclodextrin (CD) gatekeeper, which is a key element in the pro-bone-remodeling functions such as anti-inflammation and induction of M2 macrophage polarization to facilitate osteogenic differentiation. This nanosystem passively accumulated in the fracture site, promoting osteogenic differentiation activities, highlighting a potent therapeutic benefit with high biosafety.

Baicalein 5,6-Dimethyl Ether Prevents Memory Deficits in the Scopolamine Zebrafish Model by Regulating Cholinergic and Antioxidant Systems

Baicalein 5,6-dimethyl ether, a bioactive flavonoid isolated for the first time from Alnus rugosa, was explored for its capability to relieve memory deficits and decrease oxidative stress. We examined the neuropharmacological effects of baicalein 5,6-dimethyl ether on scopolamine (Sco)-induced zebrafish (Danio rerio) anxiety, amnesia, and brain oxidative stress and attempted to elucidate the underlying mechanisms. Anxiety-like behavior, exploratory behavior, and memory performance were measured using novel tank-diving test (NTT), Y-maze, and novel object recognition (NOR) tests. For 10 days, baicalein 5,6-dimethyl ether (1, 3, and 5 µg/L) was administered through immersion, whereas Sco (100 μM) was delivered 30 min before behavioral tests. Treatment with baicalein 5,6-dimethyl ether reduced anxiety and memory impairment, and increased exploratory behavior in specific tests, along with significant protection from neuronal oxidative stress in the brain tissue of Sco-treated zebrafish. Antioxidant and anti-acetylcholinesterase (AChE) activities of baicalein 5,6-dimethyl ether in the Sco-induced zebrafish were further confirmed using in vivo assays. In Sco-treated zebrafish, baicalein 5,6-dimethyl ether regulated cholinergic function by inhibiting AChE activity. Baicalein 5,6-dimethyl ether may be a promising candidate compound for treating anxiety and amnesia by restoring cholinergic activity and reducing brain oxidative stress, according to our findings.

Nanoengineering Branched Star Polymer-Based Formulations: Scope, Strategies, and Advances

Soft nanoparticles continue to offer a promising platform for the encapsulation and controlled delivery of poorly water-soluble drugs and help enhance their bioavailability at targeted sites. Linear amphiphilic block copolymers are the most extensively investigated in formulating delivery vehicles. However, more recently, there has been increasing interest in utilizing branched macromolecules for nanomedicine, as these have been shown to lower critical micelle concentrations, form particles of smaller dimensions, facilitate the inclusion of varied compositions and function-based entities, as well as provide prolonged and sustained release of cargo. In this review, it is aimed to discuss some of the key variables that are studied in tailoring branched architecture-based assemblies, and their influence on drug loading and delivery. By understanding structure-property relationships in these formulations, one can better design branched star polymers with suitable characteristics for efficient therapeutic interventions. The role played by polymer composition, chain architecture, crosslinking, stereocomplexation, compatibility between polymers and drugs, drug/polymer concentrations, and self-assembly methods in their performance as nanocarriers is highlighted.

Miktoarm Star Polymers: Branched Architectures in Drug Delivery

Delivering active pharmaceutical agents to disease sites using soft polymeric nanoparticles continues to be a topical area of research. It is becoming increasingly evident that the composition of amphiphilic macromolecules plays a significant role in developing efficient nanoformulations. Branched architectures with asymmetric polymeric arms emanating from a central core junction have provided a pivotal venue to tailor their key parameters. The build-up of miktoarm stars offers vast polymer arm tunability, aiding in the development of macromolecules with adjustable properties, and allows facile inclusion of endogenous stimulus-responsive entities. Miktoarm star-based micelles have been demonstrated to exhibit denser coronae, very low critical micelle concentrations, high drug loading contents, and sustained drug release profiles. With significant advances in chemical methodologies, synthetic articulation of miktoarm polymer architecture, and determination of their structure-property relationships, are now becoming streamlined. This is helping advance their implementation into formulating efficient therapeutic interventions. This review brings into focus the important discoveries in the syntheses of miktoarm stars of varied compositions, their aqueous self-assembly, and contributions their formulations are making in advancing the field of drug delivery.